Lawyers for Chris Huhne's partner Carina Trimingham on Monday accused the Daily Mail at the high court in London of a "cataclysmic interference" with her private life.

Trimingham – the 44-year-old public relations adviser whose affair with the Lib Dem former energy secretary became public in June 2010, with Huhne leaving his wife of 26 years – is seeking damages from Associated Newspapers for misuse of private information and harassment. She is also seeking an injunction over 65 "highly unpleasant and hurtful" articles that have appeared since then.

Associated argues there was an important public interest and said it was entitled to report the story in full, including information that brought it to life for readers, and present it in a hard-hitting fashion.

Matthew Ryder QC, counsel for Trimingham, told Mr Justice Tugendhat the newspaper had a right to freedom of expression, but not to abuse her repeatedly under the guise of exercising that freedom. Its articles had made constant and gratuitous reference to her sexuality and previous relationship with a woman, using crude and demeaning stereotypes, and elicited offensive and sometimes homophobic comments from readers.

He added: "Miss Trimingham is not ashamed or embarrassed by her sexuality but it was private. She wished to have control about who she told and about how widely it was known. That has gone.

"The fact she entered a civil partnership is not of itself an indication that her sexuality or her relationship was something she wished to broadcast to everyone who met her."

Trimingham was not a public figure and, even if there was a public interest, it was "low to the point of being virtually negligible". Articles had referred to the "life and very different loves of the PR girl in Doc Martens", described her as a "comedy lesbian from central casting", and published an inherently private photograph of her 2007 civil partnership ceremony.

Huhne is not expected to give evidence or attend court during the five-day hearing.

Antony White QC, for Associated Newspapers, said Trimingham's case was focused not on whole articles in the Daily Mail, but isolated words or snippets of text. He added: "The evidence will show that she is not a shrinking violet but a seasoned political journalist.

"She is open about her sexuality and, perhaps most telling, she has sold stories about other people's sex lives to the press. She gives as good as she gets. She dishes it out."White said the focus of the articles was Huhne, and Trimingham's relevance was her role in the Eastleigh MP's marital breakdown, which set off the "after-shocks" they dealt with.

"She is properly in the news because she is relevant to a story about Mr Huhne."

Giving evidence, Trimingham agreed that she was Huhne's press officer in the 2007 Liberal Democrat leadership campaign and the 2010 gteneral election - two years after their affair started - but said she promoted his policies to the press rather than his personal life.

Cross-examined by White, she denied a suggestion that she had been in the past, a "habitual serial seller of titbits to the press".

She also denied that she was "robust and thick-skinned", replying: "No, or I'd hardly be sitting here today."

She agreed that, as a freelance, she had sold information to the Evening Standard, Daily Mail, Daily Star, Guardian, Sun and The People, but said it was anodyne and bland.

She agreed that she had sold information about actor Russell Crowe at a party and deputy prime minister Nick Clegg's "love life", but said it was not private information and they were not private individuals.

"I don't see how you can equate the Mail's vendetta against me with me selling a story about the deputy prime minister or a Hollywood actor."